The Middletons’ selling power

Catherine, the Duchess of Cambridge, and her younger sister, Pippa Middleton, have a unique ability to move mass quantities of the high-street brands they love. In a phenomenon dubbed the “Middleton effect,” when one of the sisters debuts a new outfit it often causes websites to crash and dresses to sell out of stock, recently in under an hour’s time. More than a year after the extravagant royal wedding, their selling power may be stronger than ever.

Catherine, Duchess of Cambridge, wore a Rebecca Taylor blue tweed jacket and matching skirt, the first time she's publicly worn the label, to a charity event at the end of April. Within 30 minutes the jacket sold out on Neiman Marcus's Web site.POOL/REUTERS